Roof on or not?

[Shrek]

Hello all. I'm looking for advice regarding rendering.
I've had a few plasterers round to get quotes for rendering my new self built extension.
The extension roof isn't on yet.
There is a single storey lean to roof at the back.
One guy said he needs to render the wall (where the slope of the roof meets the two storey part) before the roof goes on.
The roofer said he needs to finish the roof before the walls get rendered.
Told plasterer what roofer said and he insists he needs to render first so as not to damage the finished roof. He said the roofers can put lead in place but roofer said they won't know exactly where to put lead without tiling first!
Thoughts please.

Also, I've had patio doors fitted with a wide bead of silicone sealant around the frame.
The window/doors guy said the render should cover the silicone completely once done.
The plasterer said the thin coat render is only about 12mm so won't cover it all but said he will put his own silicone bead at the joint to cover it.
Does this sound strange? Window guy said every builder/renderer he has known of has just brought the render up to the edge of the aluminium.
What are your thoughts on this also please?

Thanks in advance.

 

[Dansouthcoast84]

Hi.

its catch 22 with roofs. 9 times out of 10 the roof is done before we get there then scaffold is on top.

ideal world. get the roof.felt battened and lead on then render down to the lead. or some times we have had lead installed . we render then once scaff down roof construct.


as for silincone. you can push the angle.bead over making a thicker reveal and covering the mastic

 

[Shrek]

Thanks for the reply Dan. Is there a way to cover and board the roof to protect it. I have scaffold poles going through between the rafters but I need them shifted to get the roof on. Or would I be better asking the roofers to just put the lead in?
I'm also worried about the roofers messing up the new rendering when they finish the gable end..

 

[Rigsby]

The roofer is only thinking about himself. If the rafters are on then he will know the lead line but he will prefer to come and do it all in one go than muck about making two trips.

The chances are if you put the roof on the new roof will get mortar stained no matter how well you try and hose it off. Either get the lead on or render below what will the lead line, cut out the lead line with a disc angle grinder and slot in the lead and rely on lead mate to seal it.

Another way is have the roof felted and lathed then cover with ply. Scaffold over. You will still need the lead in for a better job. Get the mess of the rendering done then take down the scaffolding and ply boards and put your new tiles on.

The new render will go up to your frame covering the existing silicone bead. Make sure the render up to the frame has had a 1mm min expansion cut out. Apply silicne between the rendering and frame.